Minor documentation issue fixed
(Matrices.continuousRiccati/discreteRiccati contained a short description which LAPACK functions have been used to implement these functions. This documentation fragment has been removed since this was from an earlier implementation, but not the current one).

git-svn-id: https://svn.modelica.org/projects/Modelica/trunk@6136 7ce873d0-865f-4ce7-a662-4bb36ea78beb